rdma/qedr: Fix crash due to redundant release of device's qp memory

Device's QP memory should only be allocated and released by IB layer.
This patch removes the redundant release of the device's qp memory and
uses completion APIs to make sure that .destroy_qp() only return, when qp
reference becomes 0.

Fixes: 514aee660d ("RDMA: Globally allocate and release QP memory")
Link: https://lore.kernel.org/r/20211019082212.7052-1-pkushwaha@marvell.com
Acked-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: Shai Malin <smalin@marvell.com>
Signed-off-by: Alok Prasad <palok@marvell.com>
Signed-off-by: Prabhakar Kushwaha <pkushwaha@marvell.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/qedr/qedr.h

@@ -455,6 +455,7 @@ struct qedr_qp {
 	/* synchronization objects used with iwarp ep */
 	struct kref refcnt;
 	struct completion iwarp_cm_comp;
+	struct completion qp_rel_comp;
 	unsigned long iwarp_cm_flags; /* enum iwarp_cm_flags */
 };
 

drivers/infiniband/hw/qedr/qedr_iw_cm.c

@@ -83,7 +83,7 @@ static void qedr_iw_free_qp(struct kref *ref)
 {
 	struct qedr_qp *qp = container_of(ref, struct qedr_qp, refcnt);
 
-	kfree(qp);
+	complete(&qp->qp_rel_comp);
 }
 
 static void

drivers/infiniband/hw/qedr/verbs.c

@@ -1357,6 +1357,7 @@ static void qedr_set_common_qp_params(struct qedr_dev *dev,
 	if (rdma_protocol_iwarp(&dev->ibdev, 1)) {
 		kref_init(&qp->refcnt);
 		init_completion(&qp->iwarp_cm_comp);
+		init_completion(&qp->qp_rel_comp);
 	}
 
 	qp->pd = pd;
@@ -2857,8 +2858,10 @@ int qedr_destroy_qp(struct ib_qp *ibqp, struct ib_udata *udata)
 
 	qedr_free_qp_resources(dev, qp, udata);
 
-	if (rdma_protocol_iwarp(&dev->ibdev, 1))
+	if (rdma_protocol_iwarp(&dev->ibdev, 1)) {
 		qedr_iw_qp_rem_ref(&qp->ibqp);
+		wait_for_completion(&qp->qp_rel_comp);
+	}
 
 	return 0;
 }